Occupational exposure to commercial cooking emissions has not been comprehensively studied, particularly in a Western context. This investigation measured the concentration and composition of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), particulate matter (PM), carbon monoxide (CO), and black carbon (BC) in 18 New York City restaurants. Eight-hour gravimetric PM1,2.5,10 mass concentrations were measured in kitchen and dining areas, and PM1 was speciated using X-ray fluorescence. Evacuated canisters and XAD-2 sorbent tubes collected VOCs and PAHs, respectively, and were speciated using gas chromatography/mass spectrometry (GC/MS). Lastly, spatial concentration gradients for PM2.5 and day-of-the-week effects were considered in eight additional restaurants. A median PM2.5 concentration of 79.6 μg/m3 was found in kitchens, with real-time values spiking into the thousands of micrograms per cubic meter in some restaurants─values below the Occupational Safety and Health Administration 8 h permissible exposure limit of 5 mg/m3 for particles not otherwise regulated (respirable fraction), but well above the 24 h World Health Organization recommended ambient exposure limit of 15 μg/m3 for 2021. Benzene, a known carcinogen, was frequently detected in the kitchen areas, while PAHs were often undetected. These data warrant further investigation into the cardiopulmonary health of restaurant workers.

Consumer-grade natural gas leaks contribute to methane-induced climate change and can degrade air quality. However, limited leakage and gas composition data exist outside of North America. Here, we measured stove-off gas leakage in 35 homes and chemically characterized 78 unburned gas samples from residential stoves across seven cities in the United Kingdom, Netherlands, and Italy. On average, benzene in unburned gas was substantially elevated compared to North America (9 to 73 times higher), while sulfur-based odorants were lower. Modeling of indoor and outdoor benzene enhancements from gas leaks showed potential for hazardous benzene exposure, often undetectable by odor. Three of 35 homes exhibited a stove-off leak that, combined with city-median benzene in gas, resulted in modeled benzene enhancements above the European Union’s annual limit value (1.6 ppbv). The combination of high benzene and relatively low odorization in natural gas suggests that hazardous leaks are likely underreported in Europe.

Natural gas and propane stoves emit benzene, a known carcinogen through combustion. This study evaluates population-level benzene exposure and associated health risks for the 6.3 million U.S. residents exposed to the top 5 % highest benzene-emitting gas stoves. We used the National Institute of Standards and Technology's CONTAM, a multizone indoor air quality model, to simulate benzene concentration distributions across 24 floorplans by integrating benzene emission rates with U.S. housing stock data. Health risks were assessed using the USEPA Health Risk Assessment methodology under scenarios of low, medium, and high stove usage with ventilated (open windows or/and hoods) and non-ventilated conditions. The results show that gas stove emissions significantly elevate cancer risks in homes with medium to high gas stove usage and inadequate ventilation. The cumulative Incremental Lifetime Cancer Risks (ILTCR) often exceeded the WHO safe threshold of 1E-06, particularly for children, whose ILTCR was 1.85 times higher (95 % CI: 1.43-2.12) than for adults in most of the high and medium gas stove usage scenarios. While cancer risks were elevated, non-cancer outcomes had hazard quotients < 1 in all scenarios. Ventilation mitigated risks, with high-efficiency (≥75 %) vented hoods notably reducing benzene exposure in kitchens. The study underscores the importance of addressing combustion-related indoor air pollutants to protect public health, particularly in households with limited ventilation.

Gas and propane stoves emit nitrogen dioxide (NO 2 ) pollution indoors, but the exposures of different U.S. demographic groups are unknown. We estimate NO 2 exposure and health consequences using emissions and concentration measurements from >100 homes, a room-specific indoor air quality model, epidemiological risk parameters, and statistical sampling of housing characteristics and occupant behavior. Gas and propane stoves increase long-term NO 2 exposure 4.0 parts per billion volume on average across the United States, 75% of the World Health Organization’s exposure guideline. This increased exposure likely causes ~50,000 cases of current pediatric asthma from long-term NO 2 exposure alone. Short-term NO 2 exposure from typical gas stove use frequently exceeds both World Health Organization and U.S. Environmental Protection Agency benchmarks. People living in residences <800 ft 2 in size incur four times more long-term NO 2 exposure than people in residences >3000 ft 2 in size; American Indian/Alaska Native and Black and Hispanic/Latino households incur 60 and 20% more NO 2 exposure, respectively, than the national average.

Previous research has shown that natural gas (NG) leaks from residential appliances are common, affecting greenhouse gas emission inventories and indoor air quality. To study these implications, we collected and analyzed 587 unburned NG samples from 481 residences over 17 North American cities for hydrocarbons, hazardous air pollutants, and organosulfur odorants. Nearly all (97% of) gas samples contained benzene (between-city mean: 2335 ppbv [95% CI: 2104, 2607]) with substantial variability between cities. Vancouver, Los Angeles, Calgary, and Denver had at least 2x higher mean benzene concentrations than other cities sampled, with Vancouver exhibiting a nearly 50x greater mean benzene level than the lowest-concentration city (Boston). We estimate that current U.S. and Canadian emissions inventories are missing an additional 25 000 [95% CI: 19 000, 34 000] and 4000 [95% CI: 3700, 5200] lbs benzene yr ^−1 through downstream NG leakage, respectively. Concentrations of odorants added for leak detection varied substantially across cities, indicating a lack of standardization. Houston, for instance, had 5x higher mean tert-butyl mercaptan levels than Toronto. Using these odorant measurements, we found that methane emissions as high as 0.0080–0.28 g h ^−1 and indoor benzene enhancements 0.0096–0.11 ppbv could go undetected by persons with an average sense of smell, with large uncertainties driven by smelling sensitivity, gas composition, and household conditions. We also observed larger leaks (>10 ppm ambient methane) in ∼4% of surveyed homes, confirming that indoor leakage occurs at varying degrees despite the presence of odorants. Overall, our results illustrate the importance of downstream NG composition to understand potential emissions, exposures, and odor-mediated leak detection levels. Given methane’s global warming potency, benzene’s toxicity, and wide variation in smelling abilities, our findings highlight the deficiencies regarding the sole reliance on odorization to alert and protect all occupants from indoor leaks.

The U.S. EnvironmentalProtection Agency estimates thatthere areover 3.2 million abandoned wells in the United States. Studies conductedon gas emissions from abandoned wells have been limited to methane,a powerful greenhouse gas, due to concerns regarding climate change.However, volatile organic compounds (VOCs), including benzene, a knownhuman carcinogen, are known to be associated with upstream oil andgas development and hence could also be released when methane is emittedto the atmosphere. In this investigation, we analyze gas from 48 abandonedwells in western Pennsylvania for fixed gases, light hydrocarbons,and VOCs and estimate associated emission rates. We demonstrate that(1) gas from abandoned wells contains VOCs, including benzene; (2)VOCs are emitted from abandoned wells, the magnitude of which dependson the flow rate and concentration of VOCs in the gas stream; and(3) nearly one-quarter of abandoned wells are located within 100 mof buildings, including residences, in Pennsylvania. Together, theseobservations indicate that further investigation is necessary to determinewhether emissions from abandoned wells pose an inhalation risk topeople living, working, or congregating near abandoned wells.

Purpose of Review Organosulfur compounds are intentionally added to natural gas as malodorants with the intent of short-term nasal inhalation to aid in leak detection. Regulatory exposure limits have not been established for all commonly used natural gas odorants, and recent community-level exposure events and growing evidence of indoor natural gas leakage have raised concerns associated with natural gas odorant exposures. We conducted a scoping review of peer-reviewed scientific publications on human exposures and animal toxicological studies of natural gas odorants to assess toxicological profiles, exposure potential, health effects and regulatory guidelines associated with commonly used natural gas odorants. Recent Findings We identified only 22 studies which met inclusion criteria for full review. Overall, there is limited evidence of both transient nonspecific health symptoms and clinically diagnosed causative neurotoxic effects associated with prolonged odorant exposures. Across seven community-level exposure events and two occupational case reports, consistent symptom patterns included: headache, ocular irritation, nose and throat irritation, respiratory complaints such as shortness of breath and asthma attacks, and skin irritation and rash. Of these, respiratory inflammation and asthma exacerbations are the most debilitating, whereas the high prevalence of ocular and dermatologic symptoms suggest a non-inhalation route of exposure. Summary The limited evidence available raises the possibility that organosulfur odorants may pose health risks at exposures much lower than presently understood, though additional dose-response studies are needed to disentangle specific toxicologic effects from nonspecific responses to noxious organosulfur odors. Numerous recommendations are provided including more transparent and prescriptive natural gas odorant use practices.

Exposure pathways to the carcinogen benzene are well-established from tobacco smoke, oil and gas development, refining, gasoline pumping, and gasoline and diesel combustion. Combustion has also been linked to the formation of nitrogen dioxide, carbon monoxide, and formaldehyde indoors from gas stoves. To our knowledge, however, no research has quantified the formation of benzene indoors from gas combustion by stoves. Across 87 homes in California and Colorado, natural gas and propane combustion emitted detectable and repeatable levels of benzene that in some homes raised indoor benzene concentrations above well-established health benchmarks. Mean benzene emissions from gas and propane burners on high and ovens set to 350 °F ranged from 2.8 to 6.5 μg min–1, 10 to 25 times higher than emissions from electric coil and radiant alternatives; neither induction stoves nor the food being cooked emitted detectable benzene. Benzene produced by gas and propane stoves also migrated throughout homes, in some cases elevating bedroom benzene concentrations above chronic health benchmarks for hours after the stove was turned off. Combustion of gas and propane from stoves may be a substantial benzene exposure pathway and can reduce indoor air quality.

Natural gas stoves in >40 million U.S. residences release methane (CH4)─a potent greenhouse gas─through post-meter leaks and incomplete combustion. We quantified methane released in 53 homes during all phases of stove use: steady-state-off (appliance not in use), steady-state-on (during combustion), and transitory periods of ignition and extinguishment. We estimated that natural gas stoves emit 0.8-1.3% of the gas they use as unburned methane and that total U.S. stove emissions are 28.1 [95% confidence interval: 18.5, 41.2] Gg CH4 year-1. More than three-quarters of methane emissions we measured originated during steady-state-off. Using a 20-year timeframe for methane, annual methane emissions from all gas stoves in U.S. homes have a climate impact comparable to the annual carbon dioxide emissions of 500 000 cars. In addition to methane emissions, co-emitted health-damaging air pollutants such as nitrogen oxides (NOx) are released into home air and can trigger respiratory diseases. In 32 homes, we measured NOx (NO and NO2) emissions and found them to be linearly related to the amount of natural gas burned (r2 = 0.76; p ≪ 0.01). Emissions averaged 21.7 [20.5, 22.9] ng NOx J-1, comprised of 7.8 [7.1, 8.4] ng NO2 J-1 and 14.0 [12.8, 15.1] ng NO J-1. Our data suggest that families who don't use their range hoods or who have poor ventilation can surpass the 1-h national standard of NO2 (100 ppb) within a few minutes of stove usage, particularly in smaller kitchens.

California hosts ∼124,000 abandoned and plugged (AP) oil and gas wells, ∼38,000 idle wells, and ∼63,000 active wells, whose methane (CH4) emissions remain largely unquantified at levels below ∼2 kg CH4 h-1. We sampled 121 wells using two methods: a rapid mobile plume integration method (detection ∼0.5 g CH4 h-1) and a more sensitive static flux chamber (detection ∼1 × 10-6 g CH4 h-1). We measured small but detectable methane emissions from 34 of 97 AP wells (mean emission: 0.286 g CH4 h-1). In contrast, we found emissions from 11 of 17 idle wells-which are not currently producing (mean: 35.4 g CH4 h-1)-4 of 6 active wells (mean: 189.7 g CH4 h-1), and one unplugged well-an open casing with no infrastructure present (10.9 g CH4 h-1). Our results support previous findings that emissions from plugged wells are low but are more substantial from idle wells. In addition, our smaller sample of active wells suggests that their reported emissions are consistent with previous studies and deserve further attention. Due to limited access, we could not measure wells in most major active oil and gas fields in California; therefore, we recommend additional data collection from all types of wells but especially active and idle wells.

Methane emissions from natural gas appliances remain the least characterized portion of the fossil-fuel supply chain. Here we examine water heaters from 64 northern California homes to (1) quantify methane emissions from natural gas leaks and incomplete combustion while off, turning on or off, and in steady-state operation from 35 homes; and (2) characterize daily usage patterns over similar to 1-2 months per water heater to estimate activity factors from 46 homes. Individual tankless water heaters emitted 2390 [95% CI: 2250, 2540] g CH4 yr(-1) on average, 0.93% [0.87%, 0.99%] of their natural gas consumed, primarily from on/off pulses. Storage water heaters emitted 1400 [1240, 1560] g CH4 yr(-1) on average, 0.39% [0.34%, 0.43%] of their natural gas consumption. Despite higher methane emissions, tankless water heaters generate 29% less CO(2)e(20) than storage water heaters because they use less energy to heat a unit of water. Scaling our measured emissions by the number of storage and tankless water heaters in the United States (56.8 and 1.2 million, respectively), water heaters overall emitted an estimated 82.3 [73.2, 91.5] Gg CH4 yr(-1), 0.40% [0.35%, 0.44%] of all natural gas consumed by these appliances, comparable in percentage to the EPA's estimate of methane emissions from upstream natural gas production.