Top UK and Chinese scientists studying air pollution in the megacity of Beijing and how it affects human health have published their final report.

A team of over 150 scientists have spent five years conducting one of the largest air pollution field campaigns in Beijing - generating new insight into air pollution and human health using novel observational and modelling tools. Among other things, they discovered that:

• Beijing’s air quality improves dramatically in the last few years, owing to the emission reductions following the implementation of clean air actions.
• Sources of key air pollutants in the city centre, including fine particles, volatile organic compounds (VOC), and black carbon are much lower than predicted, but concentrations were still relatively high in 2016 and 2017, indicating they were created outside the city centre.
• China’s clean energy transition for rural domestic use slashed ambient PM2.5 levels, but domestic solid fuel burning still created about 20% of ambient PM2.5 in 2012.
• Biomass and coal burning outside Beijing city centre produce fine particles (PM2.5) that are carried into the city by air masses along main routes out of North Shanxi Province, Heze and the neighbouring cities of Tianjin and Tangshan.
• Ozone pollution is high in summer and may worsen with future NOx and PM2.5 controls, unless key VOC emissions are regulated.
• Cutting ammonia emissions could significantly reduce concentrations of PM2.5.
• Citizens’ mental health begins to suffer when air pollution levels rise significantly. Cleaning up Beijing’s air could improve citizens’ physical and mental health.

Atmospheric Pollution and Human Health (APHH) in a Chinese Megacity (APHH-Beijing) is jointly funded by the Natural Environment Research Council (NERC) and Medical Research Council (MRC) as part of the UK-China Research and Innovation Partnership Fund, and the National Natural Science Foundation of China (NSFC).

Professor Roy Harrison, lead UK principal investigator of the largest project within APHH-Beijing (AIRPOLL), from the University of Birmingham, said: “High levels of air pollution pose a serious health risk to inhabitants of many Chinese cities. We confirmed that Beijing’s air quality has improved significantly in recent years, but air pollution levels are still well above the WHO guidelines, leading to poor health and wellbeing for over 20 million people.

“Our measurement work in Beijing has given us a much greater understanding of air pollutants in Beijing – where the pollution is coming from and how much there is. This, in turn, allows us to make recommendations to policy makers and help them make the decisions that will reduce air pollution levels in Beijing and other cities across China.”

Within the wider project, researchers also discovered that cooking oil emissions are a potential source of potentially hazardous fine particles in Beijing - suggesting that a more stringent control of this local source may be needed within the city.

Furthermore, they showed that road traffic is not a major source of primary PM2.5, but remains a significant source of NOx. Observations also confirmed that personal exposure to poor air quality in the rural area is much higher than in central Beijing, mainly due to residential coal combustion and biomass burning, with implications for inequalities in air pollution impacts.

Professor Zongbo Shi from the University of Birmingham, the science coordinator of APHH-Beijing, said: “APHH-Beijing generated a huge dataset on particulate and gaseous pollutants, health outcomes, social, economic and behavioural information, collected simultaneously in an area close to the city centre and in a rural location during two intensive campaigns.

“Analysing this rich dataset allows us to better understand how emission, chemistry and meteorology interact to determine pollution levels during winter haze events and summer smogs and gauge their impact on physical and mental health.

“The programme has enhanced UK-China collaboration, trained the next generation of scientists, and created a legacy of enhanced scientific understanding for the future that will help citizens to take individual actions to improve their day-to-day lives.”

The scientists measured air pollution in Beijing with a range of hi-tech equipment in central Beijing, including on the Institute of Atmospheric Physics’ (IAP) 325-meter meteorological tower - used to measure how pollution composition and levels change at different heights above the city.

Dr Caroline Culshaw, Head of Healthy Environment at NERC, commented: “Urban air pollution is a severe problem in many cities across the world with significant impacts on health and the economy. This report is the culmination of five years of work and highlights the new scientific knowledge from the programme along with practical approaches to reduce pollution and improve health. APHH-Beijing has been a hugely successful programme, showcasing large scale collaborative working across both national borders and the environmental and medical sciences to tackle global challenges.”

• For more information or interviews, please contact Tony Moran, International Communications Manager, University of Birmingham on +44 (0)7827 832 312. For out-of-hours media enquiries, please call: +44 (0)7789 921 165.
• The University of Birmingham is ranked amongst the world’s top 100 institutions, its work brings people from across the world to Birmingham, including researchers and teachers and more than 5,000 international students from over 150 countries.
• The APHH-Beijing project uses multiple atmospheric measurement and analysis strategies to determine where the pollution is coming from and how much there is; develop novel ways of recording emissions, and integrating these to produce new modelling tools for use in policy development.
• Partners in the Atmospheric Pollution and Human Health (APHH) in a Chinese Megacity programme include: Anhui Institute of Optics and Fine Mechanics, CAS; Cambridge University; Capital Medical University- CCMU; China University of Mining and Technology (Beijing); Chinese Research Academy of Environmental Sciences; Duke Kunhan University; Guangzhou Institute of Geochemistry, CAS; Heriot Watt University; Imperial College London; Institute of Atmospheric Physics, CAS; Institute of Occupational Medicine; King’s College London; Lancaster University; London School of Tropical Medicine-LSHTM; UK Centre for Ecology and Hydrology (UKCEH); Peking University; Tsinghua University; University of Birmingham; University of East Anglia; University of Edinburgh; University of Leeds; University of Leicester; University of Manchester; University of Reading; and University of York.