mask or no mask?

another way to phrase the above qn would be ‘N95, or no N95’? with the bad haze situation lately, this naturally becomes a FAQ 🙂

2015 Sep 25 morning, dense haze caused by PM2.5 pollution
2015 Sep 25 around 8am, dense haze caused by PM2.5 pollution from land clearing in Indonesia

the official MOH recommendation can be found here. an extract of qn 1 answers below:

– N95 masks are not needed for short exposure, like commuting from home to school or work, travel from bus-stop to shopping mall. N95 masks are also not needed in an indoor environment.

– A healthy person who has to be outdoors for several hours when the air quality is in the hazardous range (PSI >300) may reduce exposure by wearing a N95 mask.

we would see that qn 1 is written with “A Healthy person” in mind. What’s the definition of a healthy person? What are the indicators? For e.g., if I experience sinus problems, and/or blocked nose easily, and/or my nostrils partially blocked 24/7, and/or my throat is inflamed easily, am I considered ‘healthy’? The term ‘healthy’ is not well-defined; it’s ambiguous. Some may say ‘see a doctor’? Well, for those of us who have been through NS, you would know that under different circumstances, you may have to be certified to be “fit” under different labels; it’s not a simple ‘fit’, or ‘healthy; in this case. Yes, we can still see a doctor for advice, as always.

Or, as individuals we can define/judge it for ourselves too. For example, if our experience tells us that inhaling air contaminated with >56 ug/m3 of PM2.5 will cause our throats to be inflamed for a long while, we take steps to protect ourselves. If we belong to the ‘heroes’ category, we went for a 10km run when everyone’s seen in N95 (not according to MOH’s recommendation), and feel fresh and energised, give yourself a pat for inheriting excellent genes!

2015-09-25 00.39.14
2015 Sep 25 AQI(PM2.5) spot readings for 8am

In short, there’s no right or wrong, especially when we are all unique individuals. oh yes, another factor to consider is whether you like the idea of PM2.5 particles entering and residing in your respiratory system. again, ‘like’ is so subjective; you would have to judge it for yourself 😉

thanks goes to Kim Kee for inspiring this post. take care folks (:

pm2.5, how does it look like?

we know pm2.5 particulates are so small that it could be harming us when we cant see it coming, literally. here’s perhaps an illustration of what could be going into our respiratory system if we are not protecting ourselves with N95 masks:

2015-09-16 21.53.12

the ‘mickey mouse ears’ are a pair of filters from junior’s totobobo mask. the white one below is a brand new piece from the packaging. want to see more? check out a Chinese documentary below:

here’s the version with English subtitles (go straight to 5min 50sec):

[update 20/10]

some weeks ago, there’s this commentary on MyPaper touching on PM2.5 visibility issue. good to have a link to it (:

[//update]]

how to compute spot reading for PM2.5 index

it’s common knowledge to go to NEA’s hazeDOTgovDOTsg to obtain the 24-hr and 3-hr average PSI reading (:

but for whatever reason, if you would like to know the past 1-hr reading (aka spot reading) for the PM2.5 index, NEA also provides the data to us. as it is data, you will need to do some quick manual ‘computation’ to turn it into useful information. here’s the steps:

1. visit the Pollutant Concentration page

2. scroll slightly down to find the default 24-hr Sulphur Dioxide readings.

3. click on the dropdown listbox, select 1-hr PM2.5.

4. visit AQI calculator hosted by airnow.gov, and key in the readings from NEA webpage to obtain information about the air quality for the past 1-hr.

5. if you are lazy to go through steps 1-4, you could either visit the AQICN website, or download the Asia Air Quality app in Google Play Store or iOS App Store, OR

6. perform steps 1-3, and remember that any reading above 55µg/m3 is in the Unhealthy range.

Screenshot 2015-08-25 21.40.44

//update 14/9

recently i’ve been posting screenshots to fb timeline to update on AQI spot readings. these are but widgets from the asia air quality app (instructions for iOS can be found on aqicn.org)

2015-09-10 14.57.19

//update 25/9
do note that AQI & NEA’s PSI readings may not be equal. AQI shown above takes a direct computation of PM2.5 figures only. PSI on the other hand is a composite figure; the details on how to compute PSI can be found under NEA’s FAQs, or a direct link from here.

//update end