Non-methane volatile organic compounds (NMVOCs) have numerous adverse health and environmental impacts and are important ozone precursors. Despite this, these pollutants are both under-researched and inadequately addressed in policy. A new study compares measurements of NMVOCs with their representation in emission inventories. The researchers identify significant discrepancies in the data and recommend more measurements over a greater geographic area.
“NMVOCs are a very large group of organic compounds and have a significant impact on air quality. Measurements of NMVOCs are critical for understanding atmospheric chemistry, as input for air quality and climate models, and for assessing the impact of policy,” explains lead author Erika von Schneidemesser (RIFS). There is substantially more emissions data available for the United States and Asia (especially China) than for other regions. Even in Europe, few measurements are available for many types of NMVOCs.
The sources of NMVOC emissions are diverse and include industry and commerce, use of cleaners and personal care products in households and by individuals, transport, solvents, and natural sources such as forests. For the study, the researchers compiled available measurements of NMVOCs from urban areas and compared these data to emission inventories, with a particular focus on emissions from anthropogenic sources. The results revealed significant discrepancies between the available measurements and emission inventories.
“A variety of factors contribute to our understanding of NMVOCs in terms of their representation in emissions inventories and their application – for example in scientific modelling and policy assessment. One key problem is that we don’t know which factors are important. More measurements may help to address this, including longer-term monitoring and the measurement of a larger number of NMVOCs and total reactivity,” explains von Schneidemesser. This would facilitate a more accurate representation of non-methane volatile organic compounds in emission inventories, improve understanding of their role in the atmosphere, and support the evaluation of policies to reduce air pollution.