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Improving air quality in the workplace. Evidence from South Asia

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Textile garments worker male worker. | © Textile garments worker male worker. | ©

Air quality remains a global concern with South Asia, including countries like Bangladesh, India, and Pakistan, bearing the brunt of dangerously high levels of PM2.5 air pollution. This pervasive problem has not only been detrimental to public health but has also shown profound effects on worker productivity. In this blog, we explore the potential solutions to this challenge, focusing on air purifiers and their promising impact on workplace environments.

Numerous studies have demonstrated the detrimental effects of air pollution on worker productivity (Graff Zivin & Neidell, 2012; He, Liu and Salvo, 2019; Adhvaryu, Kala and Nyshadham, 2022). Regulatory failures and weak state capacity have perpetuated high pollution levels in South Asia for decades (Greenstone & Hanna, 2014).

The Role of Air Purifiers in Workplace Air Quality

Air purifiers have the potential to mitigate the adverse effects of air pollution in the workplace. However, it's crucial to understand that air purifiers, when installed solely at the workplace, can only provide limited protection for part of the day when employees are present. They are only a partial defensive investment because they are installed only in the workplace, reducing exposure to air pollution for only part of the day  when individuals are at their workplace. Furthermore, even with the use of air purifiers, indoor air pollution levels remain well above World Health Organization (WHO) standards. In the absence of a comprehensive understanding of the dose-response relationship between air pollution and productivity, it is difficult to extrapolate the extent of productivity improvements resulting from improved air quality in the workplace.

To estimate the causal impact of air purifiers on worker productivity, we initiated a randomized control trial in Bangladesh in April 2023 targeting 100 small textile firms in Dhaka. In the study, we installed air pollution monitors in all these firms, with half of them randomly selected receiving Smart Air Blast Purifiers equipped with H13 HEPA filters. These firms typically operate within single rooms, each smaller than 1400 square feet, and employ between 6 to 14 workers, with an average of just under 9 employees. Importantly, these workers are compensated based on piece-rate – directly proportional to their productivity, enabling precise tracking of individual worker productivity on any given day.

After a three-month observation period (data collection and digitization of productivity data remains ongoing), we observed remarkable effects resulting from the use of air purifiers. Factories equipped with air purifiers experienced a 37% reduction in indoor air pollution, with indoor PM2.5 concentrations measuring 25 µg/m3 lower than those without air purifiers (mean = 68 µg/m3). These are 24-hour averages, and it is worth noting that even with air purifiers, indoor air pollution levels remain well above WHO guidelines. The impact on productivity was striking, with workers in firms with air purifiers producing, on average, 27% more pieces compared to workers in firms without air purifiers.  This productivity boost could not be attributed to changes in worker hours or number of workers. An assessment of cost- effectiveness (we conduct a basic cost-benefit calculation to see the productivity returns to air purifiers. The average per unit-wage is $0.20 and the average worker in a control firm without air purifiers makes 88 pieces. On average, there are 25 working days in a month.) suggests that with a 27% treatment effect, the average firm-level gains in productivity amount to $5,710. Each air purifier, considering import duties and transportation costs, totals $700, resulting in a benefit/cost ratio of 8.15 within just one month.

These findings are preliminary, and we plan to continue measuring indoor air pollution and worker productivity over the next several months to see whether these effects continue to persist or change over time. Notably, our estimates exceed those of similar studies conducted in China (He, Liu & Salvo, 2019), India (Adhvaryu, Kala and Nyshadham, 2022) and the United States (Graff Zivin & Neidell, 2012). Several factors may account for these larger magnitudes. First, prior studies often examine the relationship between ambient air pollution, rather than indoor air pollution, and worker productivity. Infiltration coefficients, which measure the extent of outdoor PM2.5 entering indoor spaces, ranging from 0.15 to 0.3, likely contribute to the disparities in our estimates relative to prior work. Second, to the best of our knowledge, our study is the first to introduce experimental variations in air quality through the use of air purifiers. These two factors highlight the need for both measuring indoor air pollution and evaluating using an experimental benchmark when evaluating the impact of air purifiers.

If the benefits of air purifiers are substantial, why are firms not adopting them more widely? 

In our context, an obvious explanation is that firms may not be aware of these effects, and there is no domestic production of air purifiers in Dhaka, necessitating their import from China. In our future research, we aim to investigate how access to information and direct experience influence willingness to pay for clean air and how the effects of air purifiers evolve over time.

Broader Implications

Our study carries important implications for the future of cleaner air in low-and-middle income countries (LMICs). First, the productivity gap between high-income countries (HICs) and LMICs, a topic extensively discussed in economic literature, may be an important driver of these productivity gaps. In such case to boost economic growth, cities could focus on reducing air pollution.  Second, air purifiers emerge as a cost-effective solution even for small companies. By enhancing accessibility and promoting their benefits, we have the potential to raise productivity and improve the health of workers. 

These are promising early findings, our study on the impact of air purifiers on worker productivity in South Asia is ongoing, and we will share more comprehensive results in the future. In the meantime, we hope this exploration of the potential solutions to air pollution challenges contributes to the broader discussion on cleaner air in low-and-middle income countries and the well-being of workers.


Teevrat Garg

Associate Professor of Economics, School of Global Policy and Strategy, University of California in San Diego

Maulik Jagnani

Assistant Professor, Fletcher School and Department of Economics at Tufts University

Nancy Lozano Gracia

Lead Economist, The World Bank

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