Air Quality and Kids Outdoor Activities in Jakarta: When to Move a Class Indoors

The number in the app is an index, not a measurement

Open the air quality screen on a Saturday morning and you get one figure, coloured green or yellow or red, and you have about ninety seconds to decide whether your child goes to their class. It is tempting to read that figure the way you read a temperature, as a direct measurement of something in the air. It is not.

PermenLHK 14/2020, the regulation that governs the index, defines ISPU as angka yang tidak mempunyai satuan yang menggambarkan kondisi mutu udara ambien. A number that has no unit, describing the condition of ambient air.

The no-unit part is the whole point. There is no substance in the air of which the reading is a count.

What the index does is compress 7 separate pollutants into one figure. PM10, PM2.5, CO, NO2, SO2, O3 dan HC are each measured, each converted onto the same scale, and the worst performer becomes the number on your screen.

So an ISPU of 100 does not mean the air contains 100 of anything. It means one pollutant, and in Jakarta that is usually PM2.5, has reached a concentration that the regulation maps onto 100.

That conversion step is where the information you actually need gets folded away. Two mornings can land inside the same coloured band and involve air that is not remotely alike, because a band is wide and the index does not show you where inside it you are sitting.

None of this makes the index useless. It makes it a starting point rather than an answer.

The ministry publishes the underlying particulate figure separately, and states that hasil perhitungan ISPU untuk PM2.5 dilaporkan kepada masyarakat setiap jam selama 24 jam. The hourly number is there. Most parents never open it, because a colour is faster to read, and a colour is exactly the layer at which the detail disappears.

What does each ISPU band actually say about children?

The official category descriptions are worth reading slowly, because they are more specific than the colours suggest, and the point at which they change subject is the single most useful thing in this whole system. Baik runs to 50.

The description is that kualitas udara yang baik tidak memiliki efek negatif bagi kesehatan manusia, hewan, tumbuhan, maupun bangunan. Nothing to weigh up.

Sedang runs from 51 to 100, and here the wording is easy to misread. The official description is that this air tidak memengaruhi kesehatan manusia maupun hewan, tetapi memengaruhi tumbuhan yang sensitif.

It does not affect the health of humans or animals, but it does affect sensitive plants. Read that again. Across the entire Sedang band, the only sensitive thing the description names is vegetation.

Tidak Sehat runs from 101 to 200, and this is where the subject changes. The description becomes merugikan manusia dan hewan yang sensitif, harmful to sensitive humans and animals. At 101, and not before, the official wording stops talking about plants and starts talking about people.

Above that the language stops making distinctions at all. Sangat Tidak Sehat, from 201 to 300, is berpotensi merugikan semua populasi dalam suatu wilayah, potentially harmful to the entire population of an area. Berbahaya begins at 301 and is described as sangatlah berbahaya dan berdampak serius bagi kesehatan populasi.

So the structure gives you one clean line, at 101, and it is drawn around sensitive people. Whether your child counts as one of them is the next question, and the answer does not come from this regulation.

Why does one band cover such a wide spread of air?

Because the bands are not equal in width, and the Sedang band is enormous. Under the ISPU conversion table, the Sedang band begins when PM2.5 reaches 15.6 micrograms per cubic metre and continues all the way up to 55.4.

Tidak Sehat then starts at 55.5 and runs to 150.4. That means a morning reported as Sedang can be air at 15.6, or it can be air at 55.4, and the app will give you the same word for both.

Put those numbers next to the guideline figures and the size of that gap becomes obvious. The WHO guideline for PM2.5 over a 24-hour period is 15.

The bottom of the Sedang band already sits above it. The top of the Sedang band, at 55.4, sits above Indonesia's own national 24-hour standard of 55, which means air can be reported to you as merely moderate while breaching the country's own limit for the day.

This is not a flaw in the index so much as a consequence of what an index is for. It exists to give a whole city one comparable number, quickly, across 7 different pollutants. It was never designed to answer a question about one child in one park on one morning.

The practical version is short. When the app says Baik, the band is narrow enough that the label carries real information. When it says Sedang, the label has told you very little, and the underlying PM2.5 figure is worth the extra thirty seconds it takes to find.

Is air that meets the Indonesian standard safe for a child?

Compliant and safe are two different words, and here they are separated by a wide margin. Indonesia's national ambient air quality standards are set in PP 22/2021.

For PM2.5 the limit is 55 micrograms per cubic metre over 24 hours, and 15 as an annual average. For the coarser PM10 fraction it is 75 over 24 hours and 40 annually. Those are the numbers against which national compliance is judged.

The WHO guidelines revised in 2021 set the same 24-hour PM2.5 figure at 15, and the annual figure at 5. The WHO 24-hour value used to be 25, and was tightened.

Line those up and the picture is plain. Indonesia's legal 24-hour ceiling for PM2.5 is 55.

The health-based guideline for the same pollutant over the same window is 15. Air can sit comfortably inside the national standard, be reported to you as Sedang, and still be several multiples of what WHO considers acceptable for a day.

This is worth stating carefully, because it is easy to turn into either complacency or panic. The national standard is not a claim about what is harmless; it is a regulatory threshold that a country sets against what it can currently achieve.

WHO's own framing is that the guideline levels are widely unmet, noting that 99 percent of the world population in 2019 lived in places where they were not achieved, and attributing 7 million premature deaths a year to air pollution exposure. So the honest answer is no, meeting the standard is not the same as being safe, and a parent who wants a health-based line rather than a legal one has to use the guideline figure instead.

Jakarta's year has a shape, and August sits in the wrong half of it

Air quality in Jakarta is not a constant background condition. It has a season, and right now you are in it.

The pattern is driven by rain, or the absence of it. Limited rainfall during Indonesia's dry season, which runs from June to December, often worsens pollution. Nothing washes particulates out of the air, so they accumulate, and the readings that would look alarming in February become ordinary.

The annual figures give you the baseline. Jakarta's average PM2.5 concentration in 2024 was 41.7 micrograms per cubic metre, which IQAir puts at 8.3 times the WHO annual guideline of 5. That is the average across the whole year, wet months included, which means the dry-season mornings sit above it.

In August 2025, during that same dry season, Jakarta was recorded as the 3rd most polluted major city in the world at one point in the morning, with an Air Quality Index of 146. One caution on that last number, because it trips people up constantly.

IQAir reports on the United States index, and the ISPU you see in an Indonesian app is a different scale built on a different conversion table. A reading of 146 on one is not a reading of 146 on the other.

Compare like with like, and if you are making a decision about an Indonesian afternoon, use the Indonesian index or the raw PM2.5 concentration, not a number lifted from a global ranking. What the seasonality means for a family is simply that the same weekly class needs a different answer in August than it does in March, and that a rule set once in the wet season will quietly stop fitting.

Why is the same air harder on a child than on you?

Because the exposure is not the same exposure, and the body receiving it is not finished being built. WHO gives two mechanisms plainly.

The first is intake: children breathe more rapidly than adults and so absorb more pollutants. The second is position: they also live closer to the ground, where some pollutants reach peak concentrations. A five-year-old standing in the same spot as their parent is breathing different air, faster.

The scale of the problem is not marginal. WHO reported that 93 percent of the world's children under the age of 15, which is 1.8 billion children, breathe air polluted enough to put their health and development at serious risk, and describes air pollution as one of the greatest environmental risks to child health.

The effects are not confined to the obviously bad days either. WHO's finding is that air pollution is damaging children's lung function, even at lower levels of exposures, and that air pollution affects neurodevelopment, leading to lower cognitive test outcomes, negatively affecting mental and motor development. In the 2021 guideline release, the effects named in children were reduced lung growth and function, respiratory infections and aggravated asthma.

One thing the evidence here does not give you is a multiplier for effort. It is reasonable to think that a child doing sprint drills is taking in more air than a child sitting through a piano lesson, and the breathing-rate mechanism WHO describes points that way, but none of the sources above put a number on it. Treat activity level as a reason to apply your threshold more strictly on a hard training day, not as a second threshold with a number of its own.

A rule you can use on a Saturday morning

Here is the version that fits in the ninety seconds you actually have, built only from the figures above. Below 51, the class goes ahead. The official description of that band names no harm to people, animals, plants or buildings, and there is nothing further to check.

Between 51 and 100, do not stop at the label. The band spans PM2.5 from 15.6 to 55.4, and the official description names only sensitive plants, so the word Sedang is not a reassurance about your child.

Open the PM2.5 figure. If it is near the bottom of the band, treat the session as normal. If it is up near 55.4, the air is at the national 24-hour limit of 55 and far above the WHO guideline of 15, and a hard outdoor session is worth swapping for an indoor one.

At 101 and above, move it indoors. This is the band whose own official wording describes harm to sensitive humans, and the WHO evidence on breathing rate, height and lung development is what puts a child in that category.

It is the cleanest line the system gives you, and it does not require you to interpret anything. At 201 and above, and certainly at 301, there is no judgement call left to make.

Two practical notes. First, check on the morning, not the night before, since the particulate figure is published hourly rather than daily.

Second, ask the provider what their own policy is before you enrol, because a centre that has already decided what it does on a red-air day is a centre that will not leave you deciding alone in a car park. If you are choosing between outdoor and indoor options in the city, the Jakarta activity listings show which format each class actually runs in, and sports and swim providers are the ones worth asking first, since theirs are the sessions most often held in open air.

It is also worth reading this against the case for outdoor time rather than instead of it, which is set out in what the myopia trials measured. The goal is not less time outside. It is the same time outside, moved off the worst mornings.