Macau’s air is far from ‘clean’

Air pollution in Macau remains one of the city’s most tangible environmental problems, in a place that has rapidly grown wealthy thanks to the gaming industry. According to data from the Swiss company IQAir for 2024, the annual average concentration of PM2.5 fine particulate matter was 17.7 µg/m³, more than three times the World Health Organization’s recommended guideline level of 5 µg/m³. The pollution comes from a mix of sources: local emissions are compounded by the transport of pollutants from nearby Greater Bay Area cities.

What the numbers show:

• 17.7 µg/m³ — Macau’s annual average PM2.5 (IQAir, 2024)
• 5 µg/m³ — the WHO recommended level for PM2.5
• 52nd out of 138 in the ranking of the most polluted locations (IQAir)
• Hong Kong ranked 63rd, Singapore — 94th
• The number of ‘poor’ air-quality days in the Northern District rose from 9 to 20 (2023 → 2024), and in Ka Ho (Coloane) — from 25 to 34
• 253,182 cars registered as of the end of 2024; about 724 vehicles per km of road
• 12,525 electric vehicles as of January 2025, which is about 5% of the vehicle fleet

IQAir’s international assessment and Macau’s place among its neighbors

According to the World Air Quality Report 2024, Macau turned out to be dirtier than Asian megacities such as Hong Kong and Singapore. The gap with WHO guidelines is particularly concerning: the PM2.5 figure is more than three times the recommended level. This puts the compact city on a par with far larger industrial centers.

Even more telling is the government’s own report for 2024. Even under the more lenient local scale, the number of days with poor air quality increased noticeably. In the densely populated Northern District, there were twice as many, and on the relatively leafy island of Coloane, the Ka Ho area recorded 34 unfavorable days — a record in recent years.

The city remains popular despite the development of the iGaming market

For a city that actively welcomes tourists, such figures can become critical. Macau remains a popular destination for gambling tourism, despite the fact that the iGaming sector is developing ever faster. Not long ago, online casinos were considered the cutting edge, but they are increasingly being replaced by mobile apps. Today, all market leaders have such platforms – Parimatch, PinUp, Mostbet, 1xBet. And all these brands get most of their traffic from smartphone users. We saw this firsthand after we visited the site 1xbetcricketbetting.com about the 1xBet mobile app for cricket betting. Despite the fairly niche subject, the number of downloads, according to the site, is already more than 100,000. This shows that players are increasingly using apps.

But this does not prevent Macau from welcoming thousands of tourists every day who come to play in casinos. This influx results in an additional deterioration in air quality.

An expert’s view on health risks

‘Poor air has a highly damaging effect on people’s health, especially on the lungs and heart,’ notes Thomas Lei, Associate Professor at the Institute of Science and Environment at the University of Saint Joseph. According to the scientist, PM2.5 particles are so small that they can penetrate deep into lung tissue, and from there into blood vessels, triggering cardiovascular and respiratory complications.

Lei draws a clear comparison: the daily inhalation of polluted air is comparable in terms of harm to smoking, since both tobacco smoke and urban smog contain the same fine particulate matter. Ozone, whose levels in Macau remain persistently high, poses an additional risk. Its effects are associated with asthma, shortness of breath, and inflammatory processes in the lungs.

Pollution, mental health, and birth rates

A 2022 meta-analysis found a statistical association between long-term exposure to PM2.5 and NO2 and an increase in depressive conditions. A 2025 Hungarian study showed that a spike in PM2.5 and PM10 concentrations led to a 14.1% decline in birth rates the following year and a further 17.2% two years later. This year, American scientists published data on the negative impact of dirty air on embryo quality and fertility in both sexes. For Macau, where birth rates are falling rapidly and the authorities are trying to reverse the trend through financial incentives, these findings sound particularly acute.

What’s polluting the air within the city

Scientists call transport the main driver of personal exposure. Gasoline cars emit NO2 from exhaust pipes and PM10 during braking. Dense development, narrow streets, and frequent traffic lights turn street canyons into peculiar concentrators of harmful substances. The islands have two gas-fired power plants in Coloane, a waste incineration plant in Taipa, and wastewater treatment facilities, which add to the overall burden.

Transboundary transport—and why winter is worse

Macau is too small to control its own air on its own. Northern winds in winter bring pollution from the mainland part of the Greater Bay Area, and December consistently leads in the number of days that fail to meet PM2.5 and PM10 standards. In summer, the sea breeze from the south acts as a natural cleanser, carrying pollutants away from the coast.

There are regions where the opposite picture is observed. For example, in the American city of Reno, which is on its way to becoming a technology capital, the air is more polluted in summer—both because of the climate and because of wildfires.

Why the official picture may look ‘better’

Local 24-hour ‘safe’ limits for PM2.5 and SO2 are set at 50 µg/m³ (WHO Interim Target 2), whereas the ultimate WHO guideline levels are 10 and 40 µg/m³ respectively. For ozone, Macau uses Interim Target 1 of 160 µg/m³ against a recommended level of 100 µg/m³. This approach automatically increases the share of days with ‘good’ and ‘moderate’ quality in reports, creating a more optimistic picture.

What the authorities can do and how the region is acting

Potential measures include aligning the index more closely with international standards, encouraging the shift to electric vehicles through subsidies and tax exemptions, expanding the charging-station network, and large-scale reforestation (120 hectares in Coloane over the past year). The 2023 decarbonization strategy sets out peak carbon emissions by 2030 and an ambition of net zero by 2050.

At the regional level, Macau, Hong Kong, and Guangdong signed an agreement in 2014 on joint efforts to combat pollution, and in 2020 a plan was launched to share meteorological data among Greater Bay Area cities. Without these mechanisms, the transboundary factor will remain unmanageable.

Education and residents’ personal awareness also play a role. Lei insists that environmental education programs for children and adults can change attitudes toward the problem, since many judge air quality solely by the color of the sky—and that, according to the scientist, is a mistaken yardstick.

A trend toward improvement and the ozone problem

Over two decades, concentrations of PM2.5, PM10, and SO2 in Macau have steadily declined, as the government report also records. However, ozone levels remain as high as before, keeping the overall risk at a significant level.

The current exceedance of PM2.5, the rise in the number of unfavorable days in key districts, and the intertwining of local and regional causes of pollution form a picture that’s hard to call encouraging. Two questions remain open: how quickly Macau’s standards can be brought closer to the ultimate WHO guideline recommendations, and what specific measures can rein in persistently high ozone.