A global review of the state of the evidence of household air pollution's contribution to ambient fine particulate matter and their related health impacts.

Direct exposure to household fine particulate air pollution (HAP) associated with inefficient combustion of fuels (wood, charcoal, coal, crop residues, kerosene, etc.) for cooking, space-heating, and lighting is estimated to result in 2.3 (1.6-3.1) million premature yearly deaths globally. HAP emitted indoors escapes outdoors and is a leading source of outdoor ambient fine particulate air pollution (AAP) in low- and middle-income countries, often being a larger contributor than well-recognized sources including road transport, industry, coal-fired power plants, brick kilns, and construction dust. We review published scientific studies that model the contribution of HAP to AAP at global and major sub-regional scales. We describe strengths and limitations of the current state of knowledge on HAP's contribution to AAP and the related impact on public health and provide recommendations to improve these estimates. We find that HAP is a dominant source of ambient fine particulate matter (PM2.5) globally - regardless of variations in model types, configurations, and emission inventories used - that contributes approximately 20 % of total global PM2.5 exposure. There are large regional variations: in South Asia, HAP contributes âˆ¼ 30 % of ambient PM2.5, while in high-income North America the fraction is âˆ¼ 7 %. The median estimate indicates that the household contribution to ambient air pollution results in a substantial premature mortality burden globally of about 0.77(0.54-1) million excess deaths, in addition to the 2.3 (1.6-3.1) million deaths from direct HAP exposure. Coordinated global action is required to avert this burden.

Health and Climate Impacts of Scaling Adoption of Liquefied Petroleum Gas (LPG) for Clean Household Cooking in Cameroon: A Modeling Study.

BACKGROUND: The Cameroon government has set a target that, by 2030, 58% of the population will be using Liquefied Petroleum Gas (LPG) as a cooking fuel, in comparison with less than 20% in 2014. The National LPG Master Plan (Master Plan) was developed for scaling up the LPG sector to achieve this target. OBJECTIVES: This study aimed to estimate the potential impacts of this planned LPG expansion (the Master Plan) on population health and climate change mitigation, assuming primary, sustained use of LPG for daily cooking. METHODS: We applied existing and developed new mathematical models to calculate the health and climate impacts of expanding LPG primary adoption for household cooking in Cameroon over two periods: a) short-term (2017-2030): Comparing the Master Plan 58% target with a counterfactual LPG adoption of 32% in 2030, in line with current trends; and b) long-term (2031-2100, climate modeling only), assuming Cameroon will become a mature and saturated LPG market by 2100 (73% adoption, based on Latin American countries). We compared this with a counterfactual adoption of 41% by 2100, in line with current trends. RESULTS: By 2030, successful implementation of the Master Plan was estimated to avert about 28,000 (minimum=22,000, maximum=35,000) deaths and 770,000 (minimum=580,000 maximum=1 million) disability-adjusted life years. For the same period, we estimated reductions in pollutant emissions of more than a third in comparison with the counterfactual, leading to a global cooling of -0.1 milli °C in 2030. For 2100, a cooling impact from the Master Plan leading to market saturation (73%) was estimated to be -0.70 milli °C in comparison with to the counterfactual, with a range of -0.64 to -0.93 milli °C based on different fractions of nonrenewable biomass. DISCUSSION: Successful implementation of the Master Plan could have significant positive impacts on population health in Cameroon with no adverse impacts on climate. https://doi.org/10.1289/EHP4899.

A warmer policy for a colder climate: Can China both reduce poverty and cap carbon emissions?

Reducing global carbon dioxide (CO2) emissions is often thought to be at odds with economic growth and poverty reduction. Using an integrated assessment modeling approach, we find that China can cap CO2 emissions at 2015 level while sustaining economic growth and reducing the urban-rural income gap by a third by 2030. As a result, the Chinese economy becomes less dependent on exports and investments, as household consumption emerges as a driver behind economic growth, in line with current policy priorities. The resulting accumulated greenhouse gas emissions reduction 2016-2030 is about 60billionton (60Mg) CO2e. A CO2 tax combined with income re-distribution initially leads to a modest warming due to reduction in sulfur dioxide (SO2) emissions. However, the net effect is eventually cooling when the effect of reduced CO2 emissions dominates due to the long-lasting climate response of CO2. The net reduction in global temperature for the remaining part of this century is about 0.03±0.02°C, corresponding in magnitude to the cooling from avoiding one year of global CO2 emissions.

Alternative "global warming" metrics in life cycle assessment: a case study with existing transportation data.

The Life Cycle Assessment (LCA) impact category "global warming" compares emissions of long-lived greenhouse gases (LLGHGs) using Global Warming Potential (GWP) with a 100-year time-horizon as specified in the Kyoto Protocol. Two weaknesses of this approach are (1) the exclusion of short-lived climate forcers (SLCFs) and biophysical factors despite their established importance, and (2) the use of a particular emission metric (GWP) with a choice of specific time-horizons (20, 100, and 500 years). The GWP and the three time-horizons were based on an illustrative example with value judgments and vague interpretations. Here we illustrate, using LCA data of the transportation sector, the importance of SLCFs relative to LLGHGs, different emission metrics, and different treatments of time. We find that both the inclusion of SLCFs and the choice of emission metric can alter results and thereby change mitigation priorities. The explicit inclusion of time, both for emissions and impacts, can remove value-laden assumptions and provide additional information for impact assessments. We believe that our results show that a debate is needed in the LCA community on the impact category "global warming" covering which emissions to include, the emission metric(s) to use, and the treatment of time.