Two years ago the International Agency for Research on Cancer categorised diesel exhaust fumes as class one carcinogens in the same category as asbestos, arsenic and cigarette smoke. It said the scientific evidence about the harm of diesel exhaust fumes was compelling and its conclusion was that "diesel engine exhaust causes lung cancer in humans". The reason is that when diesel burns inside an engine it releases particles that stay in the airways and can trigger asthma, bronchitis and other lung conditions, including cancer.

It's a mystery to me why sunbeds are unregulated in New Zealand. We know they increase our risk of developing skin cancer and that the more people use them, and the younger they start using them, the greater their risk. We know, too, that thousands of young women use them on a regular basis, oblivious to the risks. We also know we have the highest rates of melanoma and skin cancer in the world. So why on earth wouldn't we regulate sunbeds, to reduce the significant and entirely preventable public health risk they pose?

Conservative governments all over the world seem to dislike public service broadcasting. George Bush targeted public service broadcasting; John Howard made attacking the Australian Broadcasting Corporation a regular sport, and now Tony Abbott has launched an all-out assault on the ABC, accusing it of being unpatriotic, and threatening to cut its funding.

Looking back, the once common practice of painting lead on to women's faces to lighten their skin seems bizarre. I suspect future generations will also consider it bizarre that for more than a century we routinely put mercury amalgam fillings into our teeth. Mercury is a highly toxic heavy metal - more toxic than lead and arsenic. It's also a potent neurotoxin and cell toxin, and even minute amounts of mercury pose a significant risk to our nervous, respiratory and immune systems.

I'm delighted that Labour MP Shane Jones has shone the spotlight on supermarket tactics in New Zealand. And I'm pleased, too, that the Minister of Commerce, Craig Foss, has raised it with the Commerce Commission, as there's really no other way of establishing if the claims are true, as trading relations between supermarkets and their suppliers are intensely secretive, and suppliers are unwilling to blow the whistle for fear of losing their business and access to the marketplace.

Most people will welcome Grey Power's call for an Aged Care Commissioner to tackle the rising incidence of financial abuse of vulnerable older Kiwis. This is a serious and growing problem. But why confine the role of an Aged Care Commissioner to investigating financial abuse among the elderly?

As councils head to the polls this year, local government finds itself under attack, with its powers shrunk and its autonomy undermined. Over the past four years, the Government has been quietly eroding the autonomy of local government and expanding its own powers to intervene in the affairs of councils, and direct what they can do. In the process, local government has been left in a weakened state, very much under the thumb of central government.

This week our Prime Minister will join the leaders of 15 Pacific Island countries at the 44th meeting of the Pacific Islands Forum. The 16 all-male leaders will meet for three days in the Marshall Islands, and discuss important issues such as climate change and Fiji's progress towards democratic elections next year. But let's hope they will also find time to discuss gender equality in the Pacific, and why it is that women in the Pacific are worse off, in many respects, than most other women in the world.

A decade ago it was hard to find gluten-free products in supermarkets. Today, buying gluten-free foods is one of the fastest-growing food trends, and most supermarkets have a large range of gluten-free products. According to a recent study, nearly four times as many people have coeliac disease, a chronic digestion disorder, as did in the 1950s. And as more people are diagnosed with coeliac disease, or have trouble digesting gluten, as many as a third of consumers are trying to cut back on gluten in their diet.

Pig industry's fight to stop another disease hitting NZ shows the dangers of relaxing controls for free trade. Most consumers are probably unaware that container loads of pork are flooding into New Zealand, and almost half of the pork we consume here is imported. Unfortunately, this imported pork comes from countries that harbour a nasty pig disease called Porcine Reproductive and Respiratory Syndrome, or PRRS. This disease is known as pig aids, because it suppresses their immune system and causes acute respiratory disease and high pig mortalities.