Search Climate Insights Directory

A Clean Air Task Force (CATF) study indicates that new CNG buses are not necessarily superior to new diesel buses regarding air quality or climate impact. While CNG buses may have marginally lower particulate matter and volatile organic compound emissions, they can have higher nitrogen oxide and greenhouse gas emissions. Furthermore, the higher purchase price of CNG buses may limit the number of older, high-emitting vehicles retired per dollar of capital funding, potentially resulting in lower fleet-wide emission reductions compared to a diesel fleet update. The climate impact of CNG is heavily dependent on methane leakage rates during production and the choice of Global Warming Potential (GWP) timeframes (GWP20 vs GWP100). Despite these factors, low fuel costs and federal funding structures incentivize transit agencies to choose CNG.

The analysis finds that while CNG buses offer long-term fuel cost savings and lower long-term GHG emissions (GWP100), they have higher upfront costs and higher short-term climate impacts (GWP20) due to fugitive methane emissions. In capital-constrained environments, new diesel buses may provide greater fleet-wide reductions in criteria pollutants because more units can be purchased and older buses retired per dollar spent.

The report assesses four fleet scenarios for the Tallinn Bus Company (TAK) up to 2020: continuing with conventional diesel, or transitioning to bioethanol (ED95), biodiesel (B100), or diesel-electric hybrids. While alternative fuels significantly reduce greenhouse gas emissions and external costs, they are more expensive to operate than conventional diesel. The study finds that the most cost-effective way to reduce local air pollution (PM and NOx) is simply replacing old buses with new Euro V and VI diesel models, as the emission gap between new diesel and alternative technologies has narrowed. Biodiesel offers the highest CO2 reduction potential, while hybrids provide the best fuel economy. The report recommends a diversified technology approach to mitigate risks associated with fuel prices and supply.

The Uniform World Model (UWM) is a simplified environmental impact assessment tool designed to calculate health impacts and damage costs from air pollution. It uses a few key input parameters and assumes a uniform distribution of receptors to provide a transparent alternative to complex 'black-box' software. The author validates the UWM by comparing its results with established models like CALPUFF, ISC3, EMEP, and GAINS across various scales and regions, including Europe, China, India, and the USA. Findings indicate that the UWM is robust, typically falling within a ±50% deviation range, and is particularly accurate for regional or continental estimates and tall stack emissions.

The document finds that GHG mitigation policies significantly improve air quality by reducing emissions of sulphur dioxide, nitrogen oxides, and particulate matter. In the EU27, this leads to substantial health gains, including an increase in average life expectancy by one month by 2050 and annual economic co-benefits ranging from €44 billion to €95 billion. The analysis also highlights significant benefits in China and India, where life expectancy gains are estimated at 19 and 30 months respectively by 2050. Additionally, mitigation reduces regulatory abatement costs for businesses and lessens the acidification and eutrophication of ecosystems.

A coalition of environmental organizations argues that the EPA's proposed rules for the oil and gas industry are insufficient. They demand the direct regulation of methane, the inclusion of existing sources, the elimination of exemptions for certain wells, and the regulation of hydrogen sulfide and particulate matter. The coalition also calls for more stringent toxic air pollutant limits and a more comprehensive health risk assessment for vulnerable populations.

The document argues that claims by Texas Governor Rick Perry and Luminant Generation Co. regarding the Cross-State Air Pollution Rule (CSAPR) are misleading. It contends that the rule does not jeopardize grid reliability, as new capacity additions would offset coal plant closures and many plants already possess the necessary scrubbers. The briefing further asserts that Texas was properly notified of its inclusion in the sulfur dioxide (SO2) program and that the compliance deadline is March 2013, not January 2012. It concludes that the rule is necessary for public health, estimating that by 2014 it would reduce premature deaths by 13,000-34,000.

The document details the severe health risks of diesel particulate matter, including 21,000 annual deaths and increased cancer risks. It advocates for the Diesel Emission Reduction Act (DERA) to clean up the existing fleet of 11 million heavy-duty engines and proposes the Clean Construction Act of 2011 to integrate emission controls into federally funded transportation projects, capping costs at 1% of project totals.

The Clean Air Task Force (CATF) proposes a 'Clean Construction' policy for U.S. transportation projects, requiring the use of emission control technologies like Diesel Particulate Filters (DPF) in PM2.5 non-attainment and maintenance areas. The proposal suggests funding these upgrades through project change orders, capped at 1% of total project costs, to mitigate severe health risks associated with diesel pollution while ensuring a fair bidding process for contractors.

The Powerplant Impact Estimator (PIE) is a software tool designed to quantify the human health and economic benefits of reducing fine particulate matter (PM2.5) emissions from US electric generating units. It employs a three-step damage function approach: modeling changes in ambient air quality using a Source-Receptor (S-R) Matrix, calculating reductions in adverse health effects via epidemiological concentration-response functions, and assigning economic values to these avoided effects using cost-of-illness and willingness-to-pay metrics.

The report documents that commuters in cars, buses, trains, and ferries are routinely exposed to high levels of diesel exhaust, with ultrafine particles (UFPs) serving as the most sensitive marker of fresh diesel emissions. Findings indicate that diesel soot dominates roadway particulate matter and that in-vehicle exposures are significantly higher than ambient outdoor air, particularly in 'pull' trains and highway tunnels. The study concludes that diesel particulate filters (DPFs) are highly effective at eliminating the soot plume behind vehicles, significantly improving air quality for following commuters and pedestrians.

The document advocates for targeting black carbon—a potent short-lived climate forcer—as a 'no regrets' strategy to slow near-term global warming and reduce premature deaths. It identifies diesel engines, cook stoves, and agricultural burning as primary controllable sources and proposes specific regulatory and financial mechanisms, such as diesel particulate filters and clean stove deployment, to address them.

The document details the ADAPTE project, which uses GIS to map social vulnerability and mortality risks linked to air pollution and temperature extremes in Latin American cities. It highlights that PM10 and NOx levels in Mexico City, Santiago, and Bogotá significantly exceed WHO standards and notes that respiratory and cardiovascular mortality risks vary by age group and season, particularly in Bogotá.

The report finds that Estonia's transport system is not developing sustainably, with car use and road freight growing in tandem with the economy, leading to high energy intensity and greenhouse gas emissions. While traffic fatalities have decreased significantly, urban air quality has suffered due to increased particulate matter from cars. The report compares Estonia's performance with EU averages and neighbors (Finland and Latvia), noting that Estonia has some of the least fuel-efficient new cars in Europe. Three scenarios for 2020 are analyzed: a 'BAAS' (baseline) scenario where trends continue, a 'TEHNO' scenario focusing on rapid vehicle efficiency gains, and an 'EFEKT' scenario focusing on mobility management and sustainable transport modes. The authors recommend a combination of both TEHNO and EFEKT measures, including CO2-based vehicle taxation, improved public transport and active mobility infrastructure, and integrated urban planning to decouple economic growth from transport demand.

The document identifies black carbon from diesel engines as a potent warming pollutant and proposes the widespread adoption of diesel particulate filters (DPFs) to achieve immediate climate and public health benefits in the United States.

The Clean Air Task Force (CATF) urges Congress to implement a multi-pollutant policy to address the public health and environmental crises caused by power plant emissions. CATF proposes capping sulfur dioxide at 2 million tons per year and nitrogen oxides at 1.6 million tons per year, while requiring a 95% reduction in mercury emissions. The document highlights that current regulations are insufficient to prevent 30,000 annual premature deaths or allow ecosystem recovery from acid rain. It further argues that these pollution controls are necessary prerequisites for the effective operation of carbon capture technologies and should be linked to any free carbon allowances provided under climate legislation like the Waxman-Markey bill.

The document examines the impact of emissions offsets on air quality in California under the Global Warming Solutions Act (AB 32). It highlights a University of California at Berkeley study showing that while in-state offsets produce mixed results—reducing methane but increasing nitrogen oxides (NOx)—out-of-state offsets lead to an increase in nearly every air pollutant, effectively exporting air quality co-benefits away from the state.

The document details two 2008 CARB regulations: a Global Warming Rule targeting heavy-duty truck fuel efficiency through aerodynamic features and tires, and a Smog and Particulate Rule requiring diesel particulate filters for trucks over 14,000 pounds. It highlights projected benefits, including the prevention of 9,400 premature deaths and billions in health cost savings, while suggesting further improvements to the global warming rule to cover more vehicle types.

The document identifies fine particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAH), and benzene as primary pollutants of concern in the Kathmandu Valley, with PM10 and PM2.5 levels exceeding WHO guidelines by 2 to 10 times. Road transport and re-suspended dust are the dominant sources of PM10, contributing approximately 63 percent of emissions. The brief estimates that PM10 exposure causes about 1,600 premature deaths annually, while benzene and PAH exposure increase risks of leukaemia and lung cancer. To combat this, the document recommends the implementation of the Programme for Rapid Evaluation of air Pollution (PREPair) and specific interventions including the transition to Vertical Shaft Brick Kilns, the introduction of Bus Rapid Transport, and the use of low sulphur fuels.

The document details the health risks associated with occupational exposure to diesel exhaust, specifically particulate matter, and advocates for the use of Diesel Particulate Filters (DPFs) to retrofit older engines.