Why does the haze looks denser at night? Is the current 3-hour PSI reading in Singapore sufficient? Is the N95 mask reallly useful? These and more were some of the questions tackled by Dr Erik Velasco, an air quality expert at CENSAM. With more than 15 years of air quality research under his belt, Dr Velasco has been approached by various media to give his views on the haze situation in Singapore and the region. The haze has plagued Singapore as far back as 40 years ago, in 1972. This year, air quality reached hazardous levels in late September, which resulted in the unprecedented closure of all primary and secondary schools on 25 Sep 2015. Check out Dr Velasco's interview on : 1. Channel NewsAsia - Why the haze looks denser at night 2. TODAY - Air pollution from daily sources 'also a health risk' 3. The New Paper/ AsiaOne -Q&A to clear the air about haze 4. Lianhe Zaobao (see translation below) - Experts suggest hourly PSI announcement for timely response, and Q&A on how you should cope with the haze.

Lianhe Zaobao, 16 Sep 2015 Experts Suggest Hourly PSI Announcements for Timely Response SINGAPORE — SMART research scientist Dr Erik Velasco said that since the National Environment Agency collects the concentrations of the six major pollutants each hour, they should announce the PSI hourly, so that government bodies, schools and the public can get information faster. Experts said NEA should also push out health advisories to let the public quickly decide to implement advanced haze advisory plans, and allow the government to request universities and offices to close if necessary. Dr Velasco was speaking to reporters yesterday at a Nanyang Polytechnic seminar on the “Singapore Perspective on Urban Air Quality and Public Health”. Mr Velasco said that based on studies on air quality in Mexico, America and Singapore in the last fifteen years, as Singapore seems unable to prevent the haze, it should develop a good haze emergency plan, which includes announcing timely air quality data.

He noted that in June 2014, after experiencing strong haze, NEA finally changed the announcements, but this was inadequate. NEA last year adjusted the PSI measurement previously used for 23 years. Since May, it has included small PM2.5 pollutant concentration in the calculation of the PSI. The PSI is thus calculated from six pollutants. NEA also replaced PM10 with PM2.5 as the important measure, since the primary component of the haze in the region is particulate matter. NEA also began hourly announcements of the previous hour’s PM2.5 pollutant concentration. This indicates the concentration of small particles in the air smaller or equal to 2.5 micrometres, as these small particles are believed to be the most harmful. Dr Velasco noted that since NEA already collects the concentrations of six major pollutants each hour, it should announce hourly PSI measurements, so that government bodies, schools and the public can respond in a timely way. “For example, on 14 Sep 2015 at 8PM, the PM2.5 hourly reading was as high as 341 micrograms.

At this level, schools should be closed and roads should have less cars. Even factories and petrol stations should be closed. However, the NEA only announced the 3-hour PSI, and the Ministry of Health’s advisory is based on the 24-hour PSI which does not take seriously the short-term harm of such haze exposure on people,” he said.global air duct cleaning memphis He said that hourly PM2.5 readings at 20-40 micrograms represent normal pollution circumstances. aircon cleaning services in caviteAnything above 50 is adverse.air duct cleaning services in scarborough He suggested that once PM2.5 readings go above 100, people should consider wearing face masks outside, and avoid the outdoors when it is above 150.

The NEA website said that the PM2.5 hourly readings may have large fluctuations and be affected by the weather, thus the public can only use the number to decide on immediate plans. During a haze situation, the NEA will use the 24-hour PSI to propose health advisories, because this number better reflects how much a person has been exposed to PM2.5 particles, and studies on particulate matter on human health all use the 24-hour PSI measurement. Source: Dr Erik Velasco and NEA My home does not have an air-conditioner, should I close my windows in the haze? If the home has an air-conditioner, you should close windows and use an air purifier. Even if there is no air-conditioner, you should close the windows and doors to prevent haze going in. Drink more water, and if uncomfortable visit a doctor. Is a N95 mask useful? How long should I wear it? An N95 mask can reduce exposure to particulate matter. But a mask’s protection qualities diminishes with each breath and it’s ability to filter particles lessens.

As such, replace it after 3-4 hours of use. Are air purifiers useful? Useful air purifiers are of two kinds: High-quality air purifiers, with internal static system attached. But air purifiers are expensive, costing $600-700. NEA’s website has a list of possible air purifiers to purchase.With smog dominating our life and headlines, sales of air purifiers and masks are flying off the shelves. Liu Zhihua explores how people cope with the pollution. For 30-year-old Beijing resident Xu Qiong, the first thing he does after waking up every morning is to check the air quality index on his smartphone, and then decide whether to wear a mask. He is not alone. That's the norm for many people in Beijing, Shanghai and many regions in China that are often covered by thick smog and haze. The most severe spell lasted for more than 20 days in 17 provinces, municipalities and autonomous regions in early 2013. Apps providing air quality index readings have mushroomed in the smartphone sphere, and products related to protection against air pollution, such as masks and air purifiers, are constantly sold out.

While people wait for wind and precipitation to clear the air, food that is rumored to fight against air pollution exposure, such as black fungus and pears, tops many people's shopping lists. Some multinational companies have increased the hardship allowance of their employees. For example, Japan's electronic firm Panasonic recently announced to their staff members in China that they will be paid more to compensate for the air pollution. "In the past, few had heard the term PM2.5 (particulate matter with a diameter smaller than 2.5 micrometers), but now many realize the risk of being exposed to PM2.5," says Zhang Shunan, director with the respiratory diseases department of China-Japan Friendship Hospital in Beijing. The number of Zhang's patients increases during smoggy days. As for air purifiers, sales increase in pace with growing awareness of PM2.5, but consumers may become confused on how to choose among so many brands and types, especially when there is no official criteria and testing method on an air purifier's ability to remove PM2.5 in the air, according to Wu Jixiang, an expert with Shanghai Jiaotong University.